CN113692478B

CN113692478B - Turbine stator blade, gas turbine, and method for manufacturing turbine stator blade

Info

Publication number: CN113692478B
Application number: CN202080028611.0A
Authority: CN
Inventors: 羽田哲; 冈岛芳史; 胁邦彦
Original assignee: Mitsubishi Power Ltd
Current assignee: Mitsubishi Power Ltd
Priority date: 2019-05-17
Filing date: 2020-04-08
Publication date: 2023-11-07
Anticipated expiration: 2040-04-08
Also published as: US11834962B2; DE112020001295B4; KR102634522B1; KR20210129194A; CN113692478A; WO2020235245A1; JP2020186708A; DE112020001295T5; JP7242421B2; US20230175404A1

Abstract

The turbine vane includes: wing-shaped parts; a shield provided on at least one of the tip end portion side and the base end portion side of the wing portion; and a protruding portion protruding toward a side opposite to the wing portion across the gas passage surface. The shield includes: a circumferential passage which is arranged on the trailing edge side and extends in the circumferential direction; and a plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side, the first end being connected to the circumferential passages, and the second end being open at the trailing edge end face of the shroud. The circumferential passage includes an inclined passage having a third end portion which is adjacent to the gas passage surface and projects toward the front edge side in a circumferential cross section, a fourth end portion which is formed at a position closer to the rear edge side than the third end portion, and an opening portion which is closed by a lid portion at the rear edge side end surface of the projecting portion. The axial position of the first end portion, at which the trailing edge end passage and the circumferential passage are connected, is arranged on the leading edge side from the position of the trailing edge side end surface of the protruding portion at the position at which the protruding portion and the shroud are connected.

Description

Turbine stator blade, gas turbine, and method for manufacturing turbine stator blade

Technical Field

The present invention relates to a turbine vane, a gas turbine, and a method for manufacturing the turbine vane.

Background

For example, turbine vanes used in gas turbines and the like are exposed to a fluid at a high temperature such as combustion gas, and thus have a structure for cooling. For example, in the turbine vane described in patent document 1, a vane main body (airfoil), an inner shroud, and an outer shroud are cooled by cooling air, respectively (see patent document 1).

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2018-141393

Disclosure of Invention

Problems to be solved by the invention

For example, a retainer for fixing a gas turbine vane to a casing of a gas turbine may be formed on an inner shroud so as to protrude radially inward of the gas turbine. The radially inner surface of the inner holder is in contact with and cooled by cooling air. However, since the retainer is present radially inside the region at the connecting position of the retainer, the cooling effect by the cooling air in the region radially outside the connecting position is reduced, and the temperature may be higher than that in other regions.

In view of the above, an object of at least one embodiment of the present invention is to improve the cooling effect of the shroud of the turbine vane.

Means for solving the problems

(1) The turbine vane according to at least one embodiment of the present invention includes:

wing-shaped parts;

a shroud provided on at least one of a distal end portion side and a proximal end portion side of the wing portion; and

a protruding portion protruding toward a side radially opposite to the wing portion across the gas passage surface,

the shield includes:

a circumferential passage which is arranged on the trailing edge side and extends in the circumferential direction; and

a plurality of trailing edge end passages arranged in a circumferential direction of the trailing edge side, a first end of the trailing edge end passage being connected to the circumferential passage, a second end of the trailing edge end passage being open to a trailing edge end surface of the shroud,

the circumferential passage includes an inclined passage having a third end portion near the gas passage surface and protruding toward the leading edge side in a circumferential cross section, a fourth end portion formed at the trailing edge side from the third end portion and having an opening portion closed by a lid portion at a trailing edge side end surface of the protruding portion,

an axial position of the first end portion, at which the trailing edge end portion passage and the circumferential passage are connected, is arranged on a leading edge side from a position of a trailing edge side end face of the protruding portion at a position at which the protruding portion and the shroud are connected.

For example, in the case where the cooling air is brought into contact with the surface of the shroud on the opposite side from the gas passage surface to convect the shroud, the protruding portion is present on the surface of the shroud on the opposite side from the gas passage surface in the region near the gas passage surface at the connection position of the protruding portion, and therefore the cooling effect by the cooling air may be reduced, and the temperature may be higher than in other regions.

According to the configuration of the above (1), the axial position of the first end portion where the trailing edge end passage and the circumferential passage are connected is arranged on the leading edge side from the position of the trailing edge side end surface of the protruding portion at the position where the protruding portion and the shroud are connected. Therefore, the region of the shroud near the gas passage surface at the connection position of the protruding portion can be efficiently cooled by the cooling air flowing in the plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side. Therefore, the temperature in this region can be suppressed from being higher than in other regions, and the cooling effect of the shroud of the turbine vane can be improved.

In addition, according to the configuration of (1) above, the inclined passage included in the circumferential passage has an opening portion at the trailing edge side end face of the protruding portion. In addition, in the circumferential cross section, the third end portion of the inclined passage is adjacent to the gas passage surface and protrudes toward the front edge side, and the fourth end portion of the inclined passage is formed at a position closer to the rear edge side than the one end portion. Therefore, for example, in the case of manufacturing the turbine vane having the structure of (1) above by casting, at least a part of the opening portion of the trailing edge side end surface of the protruding portion and the inclined passage connected to the opening portion are easily formed when the turbine vane is cast. This can suppress the manufacturing cost of the turbine vane.

(2) The turbine vane according to at least one embodiment of the present invention includes:

wing-shaped parts;

a protruding portion protruding toward the outside on the side radially opposite to the wing portion with the gas passage surface interposed therebetween,

the shield includes:

a circumferential passage arranged on the trailing edge side and extending in the circumferential direction; and

a plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side, a first end of the trailing edge end passage being connected to the circumferential passage, a second end of the trailing edge end passage being open to a trailing edge end surface of the shroud,

the circumferential passage includes: a central passage; and a plurality of circumferential end passages connected to both circumferential ends of the central passage, extending to the circumferential ends of the shroud,

the axial passage width of the central passage at the position where the trailing edge end passage connects with the circumferential passage is formed smaller than the axial passage width of the circumferential end passage,

the axial position of the central passage, to which the trailing edge end passage is connected, is arranged on the leading edge side from the position of the trailing edge side end surface of the protruding portion at the position where the protruding portion is connected to the shroud.

As described above, for example, when the cooling air is brought into contact with the surface of the shroud on the opposite side of the gas passage surface to cool the shroud, the protruding portion is present on the surface of the shroud on the opposite side of the gas passage surface in the region of the shroud near the gas passage surface at the connection position of the protruding portion, and therefore the cooling effect by the cooling air is reduced, and there is a possibility that the temperature may be higher than in other regions.

According to the configuration of (2) above, as described below, the region of the shroud near the gas passage surface at the connection position of the protruding portion can be cooled more efficiently by the cooling air flowing through the plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side.

That is, according to the configuration of (2) above, the axial passage width of the central passage at the position where the trailing edge end passage and the circumferential passage are connected is formed smaller than the axial passage width of the circumferential end passage. That is, the axial passage width of the circumferential end passage is larger than the axial passage width of the central passage at that position.

For example, a case is considered in which cooling air is supplied to the center passage by supplying cooling air to the circumferential end passage from the circumferential end surface side of the shroud. In order to suppress variation in the supply amounts of the respective trailing edge end passages and supply cooling air to the plurality of trailing edge end passages arranged in the circumferential direction via the circumferential passage, it is preferable to suppress pressure loss by increasing the flow path cross-sectional area of the upstream region of the circumferential passage with respect to the flow of the cooling air. According to the configuration of (2) above, the axial passage width of the circumferential end passage located upstream of the central passage is larger with respect to the flow of the cooling air. Therefore, the cooling air can be supplied to the plurality of trailing edge end passages arranged in the circumferential direction via the circumferential passage while suppressing the variation in the supply amount of each of the plurality of trailing edge end passages. This makes it possible to further efficiently cool the region of the shroud close to the gas passage surface at the connection position of the protruding portion by the cooling air flowing through the plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side.

In the configuration of (2), the position in the axial direction of the central passage to which the trailing edge end passage is connected is arranged on the leading edge side of the position of the trailing edge side end surface of the protruding portion at the position where the protruding portion is connected to the shroud. Therefore, the region of the shroud near the gas passage surface at the connection position of the protruding portion can be efficiently cooled by the cooling air flowing through the plurality of trailing edge end passages arranged in the circumferential direction of the trailing edge side. Therefore, the temperature in this region can be suppressed from being higher than in other regions, and the cooling effect of the shroud of the turbine vane can be improved.

(3) In several embodiments, in addition to the structure of (1) above, the first end in the trailing edge end passage is connected to the circumferential passage at the axially upstream end.

According to the configuration of the above (3), if the first end portion of the trailing edge end passage is connected to the axially upstream end of the trailing edge end passage, the trailing edge end passage can be made closer to the gas passage surface, and the start position (upstream end position) of the trailing edge end passage can be made closer to the leading edge side. Thus, the region of the shroud near the gas passage surface at the connection position of the protruding portion can be efficiently cooled by the cooling air flowing through the plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side.

(4) In several embodiments, in addition to the structure of (2) above, the central passage includes an inclined passage, a third end portion of which is close to the gas passage surface and protrudes toward the front edge side in a cross section viewed from the circumferential direction, and a fourth end portion of which is formed at the rear edge side from the third end portion and has an opening portion closed by a lid portion at a rear edge side end surface of the protruding portion.

According to the configuration of (4) above, the central passage included in the circumferential passage has an opening portion at the trailing edge side end face of the protruding portion. In addition, in a circumferential cross section, the third end portion of the central passage is close to the gas passage surface and protrudes toward the leading edge side, and the fourth end portion of the central passage is formed at the trailing edge side from the third end portion. Therefore, for example, in the case of manufacturing the turbine vane having the structure of (4) above by casting, it is easy to form the opening portion of the trailing edge side end surface of the protruding portion and at least a part of the central passage connected to the opening portion at the same time as casting the turbine vane. This can suppress the manufacturing cost of the turbine vane.

(5) In several embodiments, based on the structure of (1) or (3) above,

The circumferential passage includes: a central passage having the opening; and a circumferential end passage connected to both circumferential ends of the central passage, extending to the circumferential end of the shroud,

an axial passage width of the central passage at a position where the trailing edge end passage is connected to the circumferential passage is formed smaller than an axial passage width of the circumferential end passage.

According to the configuration of the above (5), as described in relation to the configuration of the above (2), the region of the shroud close to the gas passage surface at the connection position of the protruding portion can be cooled further efficiently by the cooling air flowing in the plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side.

(6) In several embodiments, in addition to any one of the structures (2), (4) or (5), a position in a blade height direction of the first end portion where the trailing edge end portion passage is connected to the circumferential end portion passage is closer to the gas passage surface side than a position in the blade height direction of the circumferential end portion passage.

According to the configuration of (6) above, since the trailing edge end passage can be brought close to the gas passage surface, the region of the shroud close to the gas passage surface at the connection position of the protruding portion can be efficiently cooled by the cooling air flowing through the plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side.

(7) In several embodiments, in addition to any one of the structures (2) or (4) to (6), the central passage may include: a first central passage formed on the gas passage surface side; and a second center passage formed on the outer side in the blade height direction from the gas passage surface than the first center passage, communicating with the first center passage, and including an opening formed on the trailing edge side end surface of the protruding portion.

(8) In several embodiments, based on the structure of (7) above,

the axial passage width of the first central passage is formed smaller than the axial passage width of the second central passage,

an axial position of the gas passage-surface-side end portion of the first center passage is closer to a leading edge side than an axial position at a connection position of the second center passage with the first center passage.

According to the configuration of the above (8), the axial passage width of the first center passage is formed smaller than the axial passage width of the second center passage, and the axial position of the gas passage-side end portion of the first center passage is closer to the leading edge side than the axial position at the connection position of the second center passage with the first center passage. Thus, the first and second substrates are bonded together, the end of the first central passage on the axially opposite side from the end on the axially leading edge side is located at a higher level than the second central passage the end of the central passage on the axially opposite side from the end on the axially leading edge side is located on the leading edge side. Therefore, if one end of the trailing edge passage is connected to the first center passage, the start position (upstream end position) of the trailing edge passage can be made closer to the leading edge side. Thus, the region of the shroud near the gas passage surface at the connection position of the protruding portion can be efficiently cooled by the cooling air flowing through the plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side.

(9) In several embodiments, based on the structure of (8) above,

the trailing edge end passage in which a plurality of the trailing edge end passages are arranged in the circumferential direction includes:

a first trailing edge end passage, the first end of the first trailing edge end passage being connected to the first central passage, the second end of the first trailing edge end passage opening at a trailing edge end face of the shroud; and

a second trailing edge end passage, the first end of the second trailing edge end passage being connected to the circumferential end passage, the second end of the second trailing edge end passage opening at a trailing edge face of the shroud.

According to the configuration of the above (9), since the configuration of the above (8) is provided, as described above, the end portion of the first central passage on the axially opposite side from the end portion of the second central passage on the axially opposite side from the end portion of the first central passage on the axially opposite side is located on the front side. Further, according to the configuration of (9) above, since the first end portion of the first trailing edge end passage is connected to the first center passage, the start position (upstream end position) of the first trailing edge end passage can be located closer to the leading edge side. Thus, the region of the shroud near the gas passage surface at the connection position of the protruding portion can be efficiently cooled by the cooling air flowing through the plurality of trailing edge end passages arranged in the circumferential direction on the trailing edge side.

In addition, according to the configuration of (9) above, since the first end of the second trailing edge end passage is connected to the circumferential end passage, the regions on both circumferential ends of the shroud can be efficiently cooled by the cooling air flowing through the second trailing edge end passage.

(10) In some embodiments, in addition to any one of the structures (7) to (9), the opening of the second central passage may extend from the trailing edge side end surface of the protruding portion to an end surface of the shroud opposite to the wing portion with the gas passage surface interposed therebetween.

(11) In several embodiments, on the basis of any one of the structures (1) to (10) above,

the shield includes:

a space portion formed by a bottom surface and an outer wall portion extending from the bottom surface in a blade height direction; and

and a side passage formed from a leading edge side to a trailing edge side of the circumferential side end portion, a leading edge end surface of the side passage communicating with the space portion, and a trailing edge end surface of the side passage communicating with the circumferential passage.

According to the configuration of (11), by supplying cooling air from the space to the side passage, the region near the side end in the circumferential direction of the shroud can be cooled in the range from the leading edge side to the trailing edge side.

(12) In several embodiments, in addition to any one of the structures (1) to (11), the shroud is an inner shroud formed on a tip end portion side of the wing portion, and an outer shroud formed on a base end portion side of the wing portion.

According to the configuration of the above (12), since the inner shroud and the outer shroud have the configurations of the above (1) and (2), respectively, the cooling effect of each of the inner shroud and the outer shroud can be improved.

(13) The gas turbine according to at least one embodiment of the present invention includes the turbine vane having any one of the configurations (1) to (12), and thus can improve the cooling effect of the shroud of the turbine vane. This contributes to improvement in the durability of the gas turbine.

(14) The manufacturing method of at least one embodiment of the present invention is a manufacturing method of a turbine vane, in which,

the turbine vane includes:

wing-shaped parts;

a protruding portion protruding toward a side opposite to the wing portion across the gas passage surface,

the manufacturing method of the turbine stationary blade at least comprises the following steps:

forming a second central passage extending in a circumferential direction by casting, the second central passage having an opening portion closed by a lid portion at a rear edge side end surface of the protruding portion;

A step of forming a first central passage extending in the circumferential direction by electric discharge machining or machining, wherein a third end portion of the first central passage is close to the gas passage surface and protrudes toward a leading edge side in a circumferential cross section, and a fourth end portion of the first central passage communicates with the second central passage; and

and forming a trailing edge end passage by the electric discharge machining or the machining, wherein a plurality of trailing edge end passages are arranged in a circumferential direction of the trailing edge side, a first end of the trailing edge end passage is connected to the first center passage, and a second end of the trailing edge end passage is opened to a trailing edge end surface of the shroud.

According to the method of (14) above, in the periphery Xiang Tonglu which is difficult to be formed only by casting, at least the first center passage and the trailing edge end passage are formed by electric discharge machining or machining, and the second center passage is formed by casting, so that machining is facilitated, the machining time is shortened, and the manufacturing cost of the turbine vane can be suppressed.

(15) In several embodiments, based on the structure of (14) above,

the method for manufacturing the turbine vane further includes a step of forming a circumferential end passage extending in the circumferential direction by electric discharge machining or machining, the circumferential end passage being connected to the first center passage and disposed between the side end of the shroud and the first center passage.

According to the configuration of (15) above, the circumferential end passage is formed by electric discharge machining or machining, and thus machining of the circumferential end passage becomes easy.

Effects of the invention

According to at least one embodiment of the present invention, the cooling effect of the shroud of the turbine vane can be improved.

Drawings

Fig. 1 is a schematic view showing the overall structure of a gas turbine.

Fig. 2 is a cross-sectional view showing a gas flow path of the turbine.

Fig. 3 is a front view illustrating vanes of several embodiments.

FIG. 4 is a top view of the inboard shroud of the vane shown in A-A view of FIG. 3.

Fig. 5 is a B-B cross-sectional view of fig. 4.

Fig. 6 is a C-C cross-sectional view of fig. 4.

Fig. 7 is a perspective view of the circumferential passage seen from the direction D in fig. 6.

Fig. 8 is a flowchart showing steps of a method of manufacturing a vane for several embodiments.

Detailed Description

Several embodiments of the present invention will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention to these, but are merely illustrative examples.

For example, the expression "in a certain direction", "along a certain direction", "parallel", "orthogonal", "central", "concentric" or "coaxial" and the like means not only such an arrangement but also a state in which the relative or absolute arrangement is shifted relatively by an angle or distance having a tolerance or to such an extent that the same function can be obtained.

For example, the expressions "identical", "equal", and "homogeneous" and the like indicate states in which things are equal, and indicate not only exactly equal states but also states in which there are tolerances or differences in the degree to which the same function can be obtained.

For example, the expression representing the shape such as a quadrangular shape and a cylindrical shape represents not only the shape such as a quadrangular shape and a cylindrical shape in a geometrically strict sense, but also the shape including a concave-convex portion, a chamfer portion, and the like within a range where the same effect can be obtained.

On the other hand, the expression "comprising," "including," "containing," "including," or "having" one component is not an exclusive expression excluding the presence of other components.

Fig. 1 is a schematic view showing the overall structure of a gas turbine, and fig. 2 is a cross-sectional view showing the gas flow path of the turbine.

In the present embodiment, as shown in fig. 1, the gas turbine 10 is configured such that a compressor 11, a combustor 12, and a turbine 13 are coaxially arranged by a rotor 14, and a generator 15 is connected to one end of the rotor 14. In the following description, the direction in which the axis of the rotor 14 extends is referred to as the axial direction Da, the circumferential direction around the axis of the rotor 14 is referred to as the circumferential direction Dc, and the direction perpendicular to the axis Ax of the rotor 14 is referred to as the radial direction Dr. The radial direction Dr is referred to as the blade height direction.

The compressor 11 compresses air AI taken in from an air intake port by a plurality of vanes and blades to generate high-temperature and high-pressure compressed air AC. The combustor 12 supplies a predetermined fuel FL to the compressed air AC and burns the fuel, thereby generating a high-temperature and high-pressure combustion gas FG. The turbine 13 drives the rotor 14 to rotate by passing the high-temperature and high-pressure combustion gas FG generated by the combustor 12 through a plurality of vanes and blades, and drives the generator 15 connected to the rotor 14.

As shown in fig. 2, in the turbine 13, the turbine vane (vane) 21 is configured such that the base end 23f side of the airfoil 23 is fixed to the inner shroud 25 and the tip end 23e side is fixed to the outer shroud 27. The turbine blade (blade) 41 is configured such that the base end 23f side of the airfoil 23 is fixed to the platform 45. The outer shroud 27 and the split ring 51 disposed on the tip end portion 23e side of the bucket 41 are supported by the casing (turbine chamber) 30 via the heat insulating ring 53, and the inner shroud 25 is supported by the support ring 31. Therefore, the combustion gas flow path 32 through which the combustion gas FG passes is formed along the axial direction Da as a space surrounded by the inner shroud 25, the outer shroud 27, the platform 45, and the split ring 51. As shown in fig. 4, the airfoil 23 is formed by a concave-side blade surface 23c as a pressure surface and a convex-side blade surface 23d as a negative pressure surface, and the airfoil 23 is formed by connecting the front edge 23a on the upstream side and the rear edge 23b on the downstream side in the axial direction of the back-side blade surface 23 d.

The inner shroud 25 and the outer shroud 27 function as gas passage surface forming members. The gas passage surface forming member is a member having a gas passage surface that divides the combustion gas flow path 32 and contacts the combustion gas FG. In the case where it is not necessary to particularly distinguish between the inner shroud 25 and the outer shroud 27, the inner shroud 25 and the outer shroud 27 may be simply referred to as the shroud 2.

Here, the vanes 21 of several embodiments will be described. Fig. 3 is a front view illustrating vanes of several embodiments. Fig. 4 is a view from A-A in fig. 3, and is a plan view in a state where the cover 29 is not provided. Fig. 5 is a B-B view of fig. 4. Fig. 6 is a C-C view of fig. 4.

As shown in fig. 3, the vane 21 of several embodiments includes an inner shroud 25 on the base end 23f side of the airfoil 23, that is, on one end in the blade height direction (inner end in the radial direction Dr), and an outer shroud 27 on the tip end 23e side, that is, on the other end in the blade height direction (outer end in the radial direction Dr).

As shown in fig. 3, the vane 21 of several embodiments includes, for example, a leading edge side holder 61 and a trailing edge side holder 63 (protruding portions) extending in the radial Dr inner direction on the opposite side of the airfoil 23 across the gas passage surface 25a, on the inner shroud 25. The leading edge side holder 61 is formed on the leading edge 23a side of the airfoil 23, and the trailing edge side holder 63 is formed on the trailing edge 23b side of the airfoil 23. The leading edge side holder 61 and the trailing edge side holder 63 are attached to the casing 30 via the support ring 31 (see fig. 2).

The passages of cooling air in the inner shroud 25 of the vane 21 according to several embodiments will be described below.

As shown in fig. 4, in the gas turbine 10 according to one embodiment, the inner shroud 25 of the vane 21 according to several embodiments includes an inner region (space portion) 255 that is a space capable of storing cooling air supplied from the outside, on the opposite side surface of the gas passage surface 25a, that is, on the inside in the radial direction Dr. The inner region 255 (space portion) is a region surrounded by a peripheral edge portion of the inner shroud 25, that is, a side end portion 251 on the side of the web blade surface 23c, a side end portion 252 on the side of the back blade surface 23d, a front edge end portion 253 on the front edge 23a side and a rear edge end portion 254 on the rear edge 23b side, which form both end portions in the circumferential direction of the inner shroud 25, and a space portion 257 and an impact space 256 (described later) which are formed to be recessed in the inner direction in the radial direction Dr. The inner region bottom surface 255a forming the bottom surface of the inner region 255 forms the inner surface of the gas passage surface 25a on the opposite side in the radial direction. That is, the space portion 257 and the impact space 256 are spaces formed by the inner region bottom surface 255a, the side end portions 251, 252 and the leading edge end portion 253, and the trailing edge end portion 254, which are outer wall portions extending in the blade height direction (radial direction) from the inner region bottom surface 255 a.

In the gas turbine 10 according to one embodiment, the cooling air CA is supplied from the outside to the space 257.

As shown in fig. 6, the collision plate 70 having a plurality of through holes 71 is disposed in the inner region 255 so as to cover the entire inner region bottom surface 255 a. In fig. 4, only a part of the collision plate 70 having the through hole 71 is shown. The inner region 255 forming the space portion is divided by the collision plate 70, and is divided into a space portion 257 inside in the radial direction Dr and an impact space 256 outside in the radial direction Dr. The space portion 257 communicates with the impact space 256 via the through hole 71 of the collision plate 70.

The cooling air CA supplied to the space portion 257 is supplied to the impingement space 256 via the through hole 71, and impingement-cools (collision-cools) the inner region bottom surface 255 a. By impingement cooling the inner region bottom surface 255a, overheating by the combustion gas of the gas passage surface 25a is suppressed. The cooling air CA discharged to the impingement space 256 surrounded by the impingement plate 70 and the inner region bottom surface 255a impingement-cools the inner region bottom surface 255a, and then is supplied to the side passages 110 and 111 (air passage 100) described later, or when discharged from film cooling holes (not shown) formed in the inner region bottom surface 255a into the combustion gas, the gas passage surface 25a is film-cooled. Depending on the shape of the airfoil, the cooling air CA after or before the impingement cooling of the inner region bottom surface 255a may be supplied to a cooling air passage (not shown) formed in the airfoil 23 to cool the airfoil 23.

The stator vanes 21 of several embodiments include an air passage 100 for allowing the cooling air CA supplied to the space 257 to flow toward the trailing edge end 254 of the inner shroud 25. The air passage 100 has side passages 110, 111, a circumferential passage 130, and a trailing edge end passage 180.

The side passages 110 and 111 are air passages formed from the front edge 23a side to the rear edge 23b side at the side ends 251 and 252 of the inner shroud 25, and openings formed in the front edge end surfaces 110a and 111a of the side passages 110 and 111 communicate with the impingement space 256, and the rear edge end surfaces 110b and 111b of the side passages 110 and 111 communicate with the circumferential passage 130. The side passage 111 is an air passage disposed near the back side blade surface 23d, and the side passage 110 is an air passage disposed near the abdomen side blade surface 23 c.

The circumferential passage 130 is an air passage disposed at the trailing edge portion 254 and extending in the circumferential direction. The end portions on both sides in the circumferential direction Dc of the circumferential passage 130 are closed by passage covers 150a and 151a described later, and are connected to the trailing edge end surfaces 110b and 111b of the side passages 110 and 111 on the upstream side in the axial direction Da. The circumferential passage 130 will be described in detail later.

The trailing edge passage 180 is an air passage constituted by a plurality of cooling holes 180a arranged in the circumferential direction of the trailing edge 254, and an upstream end (first end) 180b is connected to the circumferential passage 130, and a downstream end (second end) 180c in the axial direction Da is open to the trailing edge end surface 25c of the inner shroud 25.

In the air passage 100 of several embodiments configured as described above, the cooling air CA in the space portion 257 is supplied to the side passages 110 and 111 through the impingement space 256, and flows into the air passage 100 from the leading edge end surfaces 110a and 111a of the side passages 110 and 111. The cooling air CA flows from the leading edge 23a side to the trailing edge 23b side in the side passages 110, 111, and mainly convectively cools the side ends 251, 252. The cooling air CA flowing toward the trailing edge 23b side in the side passages 110, 111 flows from the side passages 110, 111 to the circumferential passage 130, and flows into the plurality of trailing edge end passages 180 via the circumferential passage 130, respectively. The cooling air CA flowing into the plurality of trailing edge end passages 180 flows from the upstream end 180b of the trailing edge end passage 180 toward the trailing edge end surface 25c of the inner shroud 25, and mainly convectively cools the trailing edge end 254. The cooling air CA is discharged from the trailing edge face 25c into the combustion gas.

In several embodiments of the vane 21, the circumferential passage 130 includes a central passage (inclined passage) 140. As shown in fig. 6, for example, in the center passage 140, a third end portion (first top surface 1411) which is an end portion on the outer side in the radial direction is close to the gas passage surface 25a and protrudes toward the leading edge 23a which is the upstream side in the axial direction Da in a cross section viewed from the circumferential direction. The radially inner end 1412 of the central passage 140, that is, the fourth end 1412 formed with a connection opening 1422 described later, is formed at a position closer to the trailing edge 23b than the radially outer end (the first top surface 1411). The central passage 140 has an opening 145, and the opening 145 is formed in a trailing edge side end surface 63a of the trailing edge side holder 63 and a trailing edge side lower end surface 254b of the trailing edge end portion 254, which are protruding portions, and is closed by the cover 29 (see fig. 7 described later).

In the vane 21 of the several embodiments, the position of the axial Da of the upstream end 180b, at which the trailing edge end passage 180 is connected to the circumferential passage 130, is arranged at a position closer to the leading edge 23a than the position of the trailing edge side end surface 63a of the trailing edge side holder 63 at which the trailing edge side holder 63 as the protruding portion is connected to the inner shroud 25. The position where the trailing edge side end surface 63a of the trailing edge side holder 63 is connected to the inner shroud 25 is a position where an extension line of the trailing edge side end surface 63a extending in the outer direction in the radial direction Dr intersects the inner shroud 25.

As described above, in the case where the pair of inner shrouds 25 are impingement-cooled by blowing cooling air onto the inner region bottom surface 255a, which is the surface of the inner shroud 25 on the opposite side in the radial direction from the gas passage surface 25a, the cooling air alone is insufficient to cool the trailing edge side holder 63 in the vicinity of the position where the trailing edge side holder 63 is connected.

According to the vanes 21 of several embodiments, the axial position of the upstream end 180b, at which the trailing edge end passage 180 is connected to the circumferential passage 130, is arranged at a position closer to the leading edge 23a than the position of the trailing edge side end surface 63a of the trailing edge side holder 63 at the position at which the trailing edge side holder 63 is connected to the inner shroud 25. Therefore, the region of the inner shroud 25 near the gas passage surface 25a at the connection position of the holder 63 can be efficiently cooled by the cooling air flowing in the plurality of trailing edge end passages 180 of the trailing edge end 254 arrayed in the circumferential direction. Therefore, the temperature in this region can be suppressed from being higher than in other regions, and the cooling effect of the inner shroud 25 of the vane 21 can be improved.

In addition, according to the vanes 21 of several embodiments, the central passage 140 included in the circumferential passage 130 has the opening 145 formed from the trailing edge side end surface 63a of the retainer 63 to the trailing edge side lower end surface 254b of the trailing edge end portion 254. In addition, regarding the central passage 140, in a circumferential cross section, a radially outer end (first top surface 1411) is adjacent to the gas passage surface 25a and protrudes toward the front edge 23a side, and a radially inner end is formed at a position closer to the rear edge 23b than the radially outer end (first top surface 1411). Therefore, for example, in the case of manufacturing the vane 21 of several embodiments by casting, it is easy to form at least a part of the opening 145 extending from the trailing edge side end surface 63a of the trailing edge side holder 63 to the trailing edge side lower end surface 254b of the trailing edge end portion 254 and the central passage 140 connected to the opening 145 when casting the vane 21. This can suppress the manufacturing cost of the vane 21.

In the vane 21 of several embodiments, the circumferential passage 130 includes a central passage 140, and two circumferential end passages 150, 151 connected to both circumferential ends of the central passage 140 and extending to end surfaces 251a, 252a of circumferential side ends 251, 252 of the inner shroud 25. That is, in the vane 21 of several embodiments, the central passage 140 communicates with the side passages 110, 111 via the circumferential end passages 150, 151.

In the vane 21 of the several embodiments, the axial passage width W1 of the center passage 140 at the position where the trailing edge end passage 180 and the circumferential passage 130 are connected is formed smaller than the axial passage width W2 of the circumferential end passages 150 and 151 (see fig. 6).

That is, the axial passage width W2 of the circumferential end passages 150, 151 is larger than the axial passage width W1 of the central passage 140 at the position where the trailing edge end passage 180 and the circumferential passage 130 are connected.

For example, as in the case of the vane 21 of the several embodiments, the cooling air CA is supplied from the end surfaces 251a and 252a of the side ends 251 and 252 in the circumferential direction of the inner shroud 25 to the circumferential end passages 150 and 151, and the cooling air CA is supplied to the center passage 140. In order to supply the cooling air CA to the plurality of trailing edge end passages 180 arranged in the circumferential direction via the circumferential passage 130 while suppressing the variation in the supply amount of each of the plurality of trailing edge end passages 180, it is preferable to sufficiently increase the flow path cross-sectional area of the region on the upstream side of the cooling air CA in the circumferential passage 130 to suppress the pressure loss. According to the vane 21 of several embodiments, the axial passage width of the circumferential end passages 150, 151 located on the upstream side is larger than that of the center passage 140, and the pressure loss on the inlet side where the cooling air CA of the circumferential passage 130 flows is reduced. The flow path cross-sectional areas of the circumferential end passages 150 and 151 are formed larger than the flow path cross-sectional areas of the side passages 110 and 111.

By suppressing the pressure loss in the circumferential passage 130, the pressure gradient in the circumferential direction of the circumferential passage 130 is eliminated, the inlet pressure of the cooling air CA at the upstream end 180b of the trailing edge end passage 180 is equalized, and the variation in the supply amount of the trailing edge end passage 180 is suppressed. Accordingly, the cooling air CA can be supplied to the plurality of trailing edge end passages 180 arranged in the circumferential direction via the circumferential passage 130 while suppressing the variation in the supply amounts of the plurality of trailing edge end passages 180. As a result, the region of the trailing edge holder 63 at the connection position near the gas passage surface 25a of the inner shroud 25 can be cooled more efficiently by the cooling air flowing through the plurality of trailing edge end passages 180 of the trailing edge end 254 arranged in the circumferential direction.

In the vane 21 of several embodiments, the upstream end 180b in the trailing edge end passage 180 is connected to the radially outer end (near the first top surface 1411) of the circumferential passage 130.

As described above, with respect to the circumferential passage 130, in the circumferential cross section, the radially outer end portion (in the vicinity of the first top surface 1411) approaches the gas passage surface 25a, and protrudes toward the leading edge 23a side. Therefore, if the upstream end 180b in the trailing edge end passage 180 is connected to the radially outer end (in the vicinity of the first top surface 1411) of the circumferential passage 130, the trailing edge end passage 180 can be brought close to the gas passage surface 25a, and the upstream end 180b formed with the trailing edge end passage 180 can be brought close to the leading edge 23a side. As a result, the region of the trailing edge holder 63 at the connection position near the gas passage surface 25a of the inner shroud 25 can be efficiently cooled by the cooling air CA flowing through the plurality of trailing edge end passages 180 of the trailing edge end 254 arranged in the circumferential direction.

In the vane 21 of several embodiments, as shown in fig. 6, the position in the blade height direction of the upstream end 180b where the trailing edge end passage 180 is connected to the circumferential passage 130 is closer to the gas passage surface 25a side than the position of the center in the blade height direction of the circumferential end passages 150, 151.

Accordingly, the trailing edge end passages 180 can be brought close to the gas passage surface 25a, and therefore the region of the trailing edge side holder 63 close to the gas passage surface 25a of the inner shroud 25 at the connection position can be efficiently cooled by the cooling air CA flowing through the plurality of trailing edge end passages 180 of the trailing edge end 254 arranged in the circumferential direction.

In the vane 21 of several embodiments, as shown in fig. 6, the center passage 140 may include a first center passage 1410 and a second center passage 1420 formed on the gas passage surface 25a side. The second central passage 1420 is formed at a position farther from the gas passage surface 25a toward the inner side in the blade height direction than the first central passage 1410, and communicates with the first central passage 1410, and the second central passage 1420 includes an opening 145 formed in a range from the trailing edge side end surface 63a of the trailing edge side holder 63 to the trailing edge side lower end surface 254b of the trailing edge end portion 254.

The axial passage width W1 of the first central passage 1410 is formed smaller than the axial passage width W3 of the second central passage 1420. In addition, the axial position of the leading edge end of the first top surface 1411 on the gas passage surface 25a side of the first central passage 1410 is closer to the leading edge 23a side than the connection opening 1422 at the connection position of the second central passage 1420 and the first central passage 1410.

Therefore, the trailing edge side surface 1417 on the trailing edge 23b side of the first central passage 1410 is located closer to the leading edge 23a side than the leading edge side surface 1425 on the leading edge 23a side of the second central passage 1420, and the trailing edge side surface 1417 on the trailing edge 23b side of the first central passage 1410 faces the leading edge side surface 1415 on the leading edge 23a side of the axial direction Da, in the axial direction Da, and therefore, if the leading edge side surface 1425 on the leading edge 23a side of the second central passage 1420 is closer to the leading edge 23a side of the axial direction Da than the trailing edge holder 63, the upstream end 180b of the trailing edge end passage 180 can be made closer to the leading edge 23a side if the upstream end 180b of the trailing edge end passage 180 is connected to the first central passage 1410. As a result, the region of the trailing edge holder 63 at the connection position near the gas passage surface 25a of the inner shroud 25 can be efficiently cooled by the cooling air flowing through the plurality of trailing edge end passages 180 of the trailing edge end 254 arranged in the circumferential direction.

Here, the structure of the central passage 140 and the circumferential end passages 150 and 151 constituting the circumferential passage 130 and the structure of the joint portions with the side passages 110 and 111 will be described in detail below with reference to fig. 5 to 7. Fig. 7 is a perspective view showing a part of the circumferential passage 130 and the side passages 110 and 111 as seen from the direction D in fig. 6.

As shown in fig. 5-7, the circumferential passage 130 includes a central passage 140 and circumferential end passages 150, 151. The central passage 140 is formed at a circumferential intermediate portion of the circumferential passage 130. One end of the circumferential end passages 150 and 151 on the side of the central passage 140 is connected to an end 140a (see fig. 4) of the central passage 140 in the circumferential direction Dc. The other ends of the circumferential end passages 150 and 151 are connected to the side passages 110 disposed at the side ends 251 and 252 of the inner shroud 25, respectively. The reason why the circumferential passage 130 is formed by at least a plurality of passages (in the present embodiment, the central passage 140 and the three passages of the two circumferential end passages 150 and 151) instead of one passage between the side end 251 and the side end 252 of the inner shroud 25 will be described below.

As shown in fig. 2 to 7, since the airfoil 23 of the vane 21 receives air pressure from the combustion gas in the axially downstream direction, the trailing edge side holder 63, which is a protruding portion protruding radially inward from the inner shroud 25, receives its reaction force in the axial direction. Therefore, the trailing edge side holder 63 is required to have rigidity as a strength member and a structure having a certain degree of plate thickness in the axial direction. On the other hand, the axial passage width of the circumferential passage 130 formed at the trailing edge side holder 63 at a position close to the gas passage surface 25a is the same as the passage width W1 of the first central passage 1410, and is relatively smaller than the plate thickness t in the axial direction of the trailing edge side holder 63.

One of the methods of forming the circumferential passage 130 in the trailing edge side retainer 63 is casting. However, as described above, the passage cross section of the circumferential passage 130 is smaller than the plate thickness of the trailing edge side holder 63, and therefore the core used in casting is likely to be broken, and casting may be difficult. Therefore, in the present embodiment, as the machining method, electric discharge machining or machining is applied to form the circumferential passage 130 without casting. The specific manufacturing method of the present embodiment will be described later, and a rectangular opening 145 that is long in the circumferential direction is formed in the trailing edge side end surface 63a of the trailing edge side holder 63 and the trailing edge side lower end surface 254b of the trailing edge end portion 254 along the trailing edge side end surface 63a and the trailing edge side lower end surface 254b of the trailing edge end portion 254. A passage section of the circumferential passage 130 is formed from the opening 145 toward a direction in which the trailing edge side holder 63 intersects the gas passage surface 25a of the connection airfoil 23, that is, the leading edge side end surface 63b of the trailing edge side holder 63.

However, in the machining method in which electric discharge machining or machining is performed only from the opening 145, the capacity of the second central passage 1420 is extremely large compared to the first central passage 1410, and the machining time is long. Thus, in the present embodiment, the circumferential passage 130 is formed by a combination of casting and electric discharge machining or machining. That is, as described above, the central passage 140 forming the intermediate portion of the circumferential passage 130 is formed of the second central passage 1420 formed by casting on the radially inner side and the first central passage 1410 formed by electric discharge machining on the radially outer side of the second central passage 1420, and the passage section of the first central passage 1410 extends obliquely toward the gas passage surface 25a toward the leading edge 23 a. By combining the two processing methods, shortening of the processing time is achieved.

On the other hand, from the viewpoint of rigidity of the trailing edge side holder 63, it is not preferable to use the structure of the central passage 140 in which the electric discharge machining or the machining and the casting are combined as described above, to the end surfaces 251a, 252a of the circumferential side end portions 251, 252 to form the circumferential passage 130. That is, according to this processing method, the opening 145 that opens at the trailing edge side end face 63a of the trailing edge side holder 63 is formed from the end face 251a of the side end portion 251 to the end face 252a of the side end portion 252, and it is not preferable in terms of strength for the trailing edge side holder 63 that requires a certain degree of rigidity. Therefore, as a path connecting the end 140a of the central passage 140 forming the intermediate portion of the circumferential passage 130 and the side passages 110, 111 of the side ends 251, 252, it is preferable that no opening is provided in the trailing edge side end surface 63a and the leading edge side end surface 63b of the trailing edge side holder 63, and a connection path formed of a circumferential through hole maintaining a necessary strength is formed in the trailing edge side holder 63.

Fig. 7 is a perspective view of the circumferential passage 130 as seen from the direction D in fig. 6. The structure other than the side passages 110, 111 and the circumferential passage 130 is shown by phantom lines. The circumferential passage 130 is indicated by a solid line (a part of a broken line), and the side passages 110 and 111 are indicated by broken lines.

As shown in fig. 6 and 7, circumferential end passages 150 and 151 are formed on both circumferential sides with a cavity 146 (second central passage 1420) that forms a part of the central passage 140 interposed therebetween. As described above, at the circumferential positions where the circumferential end passages 150 and 151 are arranged, openings are not formed in both the trailing edge side end surface 63a and the leading edge side end surface 63b of the trailing edge side holder 63. That is, between the circumferential end surfaces 1423, 1424 of the second central passage 1420 and the circumferential end surfaces 251a, 252a of the inner shroud 25, only the circumferential end passages 150, 151 penetrating the inside of the trailing edge side holder 63 in the circumferential direction are provided, and no openings are formed in the trailing edge side end surface 63a and the leading edge side end surface 63b of the trailing edge side holder 63. In order to secure the necessary rigidity of the trailing edge side holder 63, the following structure is adopted: between the intermediate portion of the trailing edge side holder 63 and the end surfaces 251a, 252a of the inner shroud 25, circumferential end passages 150, 151 penetrating the inside of the trailing edge side holder 63 in the circumferential direction are arranged without openings directly connecting the outer surfaces of the leading edge 23a side and the trailing edge 23b side of the trailing edge side holder 63. The circumferential end passages 150, 151 are connection passages that maintain the rigidity of the trailing edge side retainer 63 and form a part of the circumferential passage 130.

The side passages 110, 111 may be formed by any of casting or electrical discharge machining or machining. Therefore, after the side passages 110, 111 are formed in the side ends 251, 252, if the circumferential end passages 150, 151 are formed so as to overlap the circumferential end passages 150, 151 in a radial cross-section in the vicinity of the trailing edge end surfaces 110b, 111b of the side passages 110, 111, the circumferential end passages 150, 151, and the central passage 140 can be joined by one-pass machining. When the circumferential end passages 150 and 151 are machined, passages extending from the end surfaces 251a and 252a of the side ends 251 and 252 in the circumferential direction to the central passage 140 (first central passage 1410) are formed. That is, the pair of circumferential end passages 150, 151 also function as connecting passages formed in a different processing step than the center passage 140 and the side passages 110, 111. As a target to which the connection path is applied, not only the paths (the side paths 110 and 111 and the first central path 1410) are connected as in the present embodiment, but also either one may be a space.

A more specific configuration will be described with reference to fig. 5 to 7. The second central passage 1420, which constitutes a part of the central passage 140, includes an opening 145 formed from the trailing edge side end surface 63a to the trailing edge side lower end surface 254b of the trailing edge side holder 63, and is formed as a cavity 146 extending in the circumferential direction and the leading edge 23a direction. The opening 145 is sealed by welding and fixing the cover 29. The opening 145 of the cavity 146 is formed across the trailing edge side end surface 63a and the trailing edge side lower end surface 254 b. The cavity 146 is a space surrounded by a leading edge side end surface 1425 and a trailing edge side end surface 1427 of the second central passage 1420, a second top surface 1421 near the gas passage surface 25a, and circumferential end surfaces 1423 and 1424 formed at both ends in the circumferential direction. A connection opening 1422 connected to the first central passage 1410 is opened on the front edge 23a side of the second top surface 1421 at the radial end of the cavity 146.

A first central passage 1410 extending in the direction of the leading edge 23a and in the radially outer direction is formed from the connection opening 1422. The first central passage 1410 is formed by a leading edge side surface 1415 and a trailing edge side surface 1417 that are axially opposed and extend in the circumferential direction, and is a passage in the shape of a flat plate extending in the circumferential direction. The radially outer end of the first central passage 1410 is a machining end at the time of electric discharge machining, and is closed by a first top surface 1411. The trailing edge side surface 1417 is a position where the upstream end 180b of the trailing edge end passage 180 is connected, and the trailing edge end passage 180 opens on the trailing edge side surface 1417. In order to strengthen the cooling of the trailing edge side holder 63 and the trailing edge side holder 63 in the vicinity of the gas passage surface 25a connecting the airfoil portion 23, it is preferable that the trailing edge side surface 1417 is made as close to the leading edge 23a side as possible, and the length of overlap between the trailing edge end passage 180 and the trailing edge side holder 63 when viewed in the radial direction is made longer. The connection opening 1422 is a processing start position connected to the first central passage 1410 and forming the first central passage 1410 by electric discharge machining.

Next, the positional relationship between the first central passage 1410 and the circumferential end passages 150, 151 and the side passages 110, 111 will be described. As shown in fig. 5, the radial height of the leading edge side end surfaces 150b, 151b of the circumferential end passages 150, 151 at the positions where the side passages 110, 111 are connected to the circumferential end passages 150, 151 is preferably equal to or greater than the radial height of the side passages 110, 111. The positions of the top upper surfaces 150d, 151d forming the radially outer sides of the passage sections of the circumferential end passages 150, 151 are preferably the same positions as the upper surfaces 110c, 111c of the side passages 110, 111 or positions of the gas passage surface 25a beyond the upper surfaces 110c, 111c and closer to the upper surfaces 110c, 111 c. When the discharge machining of the circumferential end passages 150, 151 is performed as the connection passages after the machining of the side passages 110, 111, the entire surfaces of the passage cross sections of the side passages 110, 111 penetrate the leading edge side end surfaces 150b, 151b of the circumferential end passages 150, 151. As a result, the passage cross-sectional areas of the connection openings 110e and 111e formed at the connection positions of the side passages 110 and 111 and the circumferential end passages 150 and 151 can be sufficiently ensured, and the occurrence of excessive pressure loss of the cooling air at the connection openings 110e and 111e can be suppressed.

As shown in fig. 5 to 7, circumferential inner end portions 150g and 151g on the circumferentially opposite sides of the circumferential outer end portions 150f and 151f, which are connected to the side passages 110 and 111, are connected to the first central passage 1410. The radial positional relationship between the first central passage 1410 and the circumferential end passages 150, 151 is preferably such that the position of the radial Dr of the first top surface 1411 of the first central passage 1410 is formed at the same height as or slightly radially outward of the position of the radial Dr of the top upper surfaces 150d, 151d of the circumferential end passages 150, 151, closer to the gas passage surface 25a. If the position of the first top surface 1411 of the first central passage 1410 in the radial direction Dr can be made closer to the gas passage surface 25a, the position of the trailing edge end passage 180 connected to the first central passage 1410 in the radial direction can be made closer to the gas passage surface 25a, and cooling of the lower portion of the trailing edge side holder 63 (the connecting end of the trailing edge side holder 63 to the inner shroud 25) can be enhanced.

As shown in fig. 5 and 6, the positional relationship between the first central passage 1410 and the circumferential end passages 150 and 151 in the axial direction (leading-trailing direction) is preferably such that the positions of the leading end surfaces 150b and 151b of the circumferential end passages 150 and 151 are located as close as possible to the positions of the leading end 1413a of the first top surface 1411 of the first central passage 1410 and the leading end surface 63b of the trailing retainer 63. However, in view of the strength of the trailing edge side retainer 63, it is necessary to provide a certain distance between the leading edge side end surfaces 150b, 151b of the circumferential end passages 150, 151 and the leading edge side end surface 63b of the trailing edge side retainer 63 to maintain the minimum plate thickness. Therefore, the positions of the leading edge side end surfaces 150b, 151b of the circumferential end passages 150, 151 are preferably formed as close as possible to the axially downstream side (trailing edge 23b side) of the leading edge side end surface 63b of the trailing edge side holder 63 within a predetermined plate thickness required in terms of retained strength.

The passage cross-sectional area of the circumferential end passages 150, 151 is preferably larger than the passage cross-sectional area of the side passages 110, 111 arranged upstream in the flow direction of the cooling air. On the other hand, the circumferential end passages 150, 151 have rectangular cross-sectional shapes surrounded by 4 surfaces of leading edge side end surfaces 150b, 151b, trailing edge side end surfaces 150c, 151c, top upper surfaces 150d, 151d, and bottom surfaces 150e, 151 e. As described above, the circumferential end passages 150, 151 penetrate the end surfaces 251a, 252a of the side ends 251, 252, and therefore the radial height of the rectangular cross section is limited to a height substantially equal to the passage height of the side passages 110, 111. On the other hand, the minimum necessary passage width for the axial passage width W2 of the circumferential end passages 150, 151 having a rectangular cross section is determined by the larger passage width of the axial passage width W1 of the first central passage 1410 or the passage width determined according to the passage sectional area of the circumferential end passages 150, 151. Therefore, from the viewpoint of reducing the pressure loss of the cooling air, it is preferable that the axial passage width W2 of the circumferential end passages 150, 151 is at least 2 times or more the axial passage width W1, and the passage cross-sectional area of the circumferential end passages 150, 151 is a passage width larger than the passage cross-sectional area of the side passages 110, 111.

As shown in fig. 7, the cooling air CA supplied to the side passages 110, 111 flows into the circumferential end passages 150, 151 via connection openings 110e, 111e formed in leading edge side end surfaces 150b, 151b of the circumferential end passages 150, 151, which are connected to the circumferential end passages 150, 151 in the side passages 110, 111. Further, connection openings 150h and 151h for connecting the first central passage 1410 to the circumferential end passages 150 and 151 are formed in the circumferential inner end portions 150g and 151g of the circumferential end passages 150 and 151 where the first central passage 1410 is connected to the circumferential end passages 150 and 151. The cooling air CA supplied to the circumferential end passages 150, 151 is supplied to the first central passage 1410 via the connection openings 150h, 151h. The first central passage 1410 extending from the connection opening 1422 of the second central passage 1420 in the direction of the leading edge 23a and the radially outer direction is indicated by a broken line, and is connected to the circumferential end passages 150 and 151 via the connection openings 150h and 151h.

As described above, the circumferential end passages 150 and 151 are disposed at both circumferential ends connected to the side ends 251 and 252, not at the intermediate portion of the circumferential passage 130 of the trailing edge end 254 of the inner shroud 25. Therefore, since neither the trailing edge side end surface 63a nor the leading edge side end surface 63b of the trailing edge side holder 63 is provided with an opening, a passage penetrating the trailing edge side holder 63 in the circumferential direction Dc is formed, and thus the required rigidity of the trailing edge side holder 63 is maintained.

The radially outer trailing edge side end surface (trailing edge side surface 1417) of the central passage 140, which is adjacent to the gas passage surface 25a, connected to the trailing edge end passage 180 is disposed at a position closer to the leading edge 23a than the position of the trailing edge side end surface 63a of the trailing edge holder 63 in the axial direction Da. When the central passage 140 is viewed in the circumferential direction Dc, the position of the central passage 140 in the axial direction Da is located closer to the leading edge 23a than the position of the trailing edge side end surface 63a of the trailing edge side holder 63 in the axial direction Da. In particular, the central passage (first central passage 1410) to which the trailing edge end passage 180 is connected forms an inclined passage inclined toward the leading edge 23a side, close to the leading edge 23a, and close to the gas passage surface 25a, and is arranged closer to the leading edge 23a side than the second central passage 1420 that is a part of the central passage 140. Therefore, the position of the axial direction Da of the center passage (first center passage 1410) is arranged closer to the leading edge 23a than the position of the axial direction Da of the trailing edge side end surface 63a of the trailing edge side holder 63, and is effective for cooling the inner shroud 25 on the leading edge 23a side in the vicinity of the position where the trailing edge side holder 63 is connected to the inner shroud 25. Therefore, in the radial Dr cross section, the trailing edge side retainer 63 and the trailing edge end passage 180 are arranged so as to overlap, and the root of the trailing edge side retainer 63, that is, the position where the trailing edge side retainer 63 and the inner shroud 25 are connected, is efficiently cooled by the trailing edge end passage 180, thereby improving the reliability of the blade.

In the vane 21 of several embodiments, the plurality of trailing edge end passages 180 arranged in the circumferential direction include a first trailing edge end passage 181 and a second trailing edge end passage 182. The upstream end 180b of the first trailing end passage 181 is connected to the first central passage 1410, and the trailing end surface 254a opens at the trailing end surface 25c of the inner shroud 25. The upstream end 180b of the second trailing edge end passage 182 is connected to the circumferential end passages 150, 151, and the trailing edge end surface 254a is open to the trailing edge end surface 25c of the inner shroud 25.

As described above, the trailing edge side surface 1417 in the first central passage 1410 is located closer to the leading edge 23a than the trailing edge side end surface 1427 in the second central passage 1420. Further, since the upstream end 180b of the first trailing edge end passage 181 is connected to the first central passage 1410, the upstream end 180b, which is the upstream end position of the first trailing edge end passage 181, can be located closer to the leading edge 23a side. As a result, the region of the trailing edge portion 254 near the gas passage surface 25a of the inner shroud 25 at the connection position of the retainer 63 can be efficiently cooled by the cooling air CA flowing through the plurality of trailing edge portion passages 180 (the first trailing edge portion passages 181) arranged in the circumferential direction Dc.

In addition, according to the vanes 21 of several embodiments, the upstream ends 180b of the second trailing edge end passages 182 are connected to the circumferential end passages 150, 151, and therefore the regions on both end sides in the circumferential direction Dc of the inner shroud 25 can be efficiently cooled by the cooling air CA flowing in the second trailing edge end passages 182.

In the vane 21 of the several embodiments, the opening 145 of the second center passage 1420 may extend from the trailing edge side end surface 63a of the retainer 63 to the trailing edge side lower end surface 254b of the inner shroud 25 on the opposite side of the airfoil 23 with the gas passage surface 25a interposed therebetween.

In the vane 21 of several embodiments, as described above, the shroud 2 includes the space portion 257 and the impingement space 256 and the side passages 110, 111.

By this, by supplying the cooling air CA from the space portion 257 to the side passages 110, 111 via the impingement space 256, the region in the vicinity of the side ends 251, 252 of the inner shroud 25 in the circumferential direction Dc can be cooled in the range from the front edge 23a side to the rear edge 23b side.

In the above description, the air passage 100 in the inner shroud 25 is described, but the air passage in the outer shroud 27 may have the same structure as the air passage 100 in the inner shroud 25. This can improve the cooling effect in the inner shroud 25 and the outer shroud 27, respectively.

Since the gas turbine 10 according to the above-described embodiment includes the vanes 21 according to several embodiments, the cooling effect of the vanes 21 on the shroud 2 can be improved. This helps to improve the durability of the gas turbine 10.

(method for manufacturing stator blade 21)

Hereinafter, a method for manufacturing the stator vanes 21 according to the above-described embodiments will be described. As described above, in several embodiments, the vane 21 is manufactured by a manufacturing method including casting and electric discharge machining or machining.

Fig. 8 is a flowchart showing steps of a method of manufacturing the vane 21 for several embodiments. The method for manufacturing the stator blade 21 according to several embodiments includes: a casting step S10, an electric discharge machining step S20, and an opening closing step S30.

The casting step S10 is a step of casting the vane 21 in which the airfoil 23, the inner shroud 25, and the outer shroud 27 are integrally formed. In the casting step S10 of several embodiments, the side passages 110 and 111 and the second central passage 1420 including the opening 145 are formed by casting. That is, the casting step S10 of several embodiments includes a first step of forming the second central passage 1420 as a part of the circumferential passage 130 by casting (circumferential passage forming first step S11).

The side passages 110 and 111 may be formed not in the casting step S10 but in the electric discharge machining step S20 described later.

The electric discharge machining step S20 is a step of forming the first center passage 1410, the circumferential end passages 150 and 151, and the trailing edge end passage 180 by electric discharge machining or mechanical machining for the vane 21 formed by the casting step S10. That is, the electric discharge machining process S20 according to several embodiments includes: a second step of forming a first central passage 1410, which is an unprocessed portion of the circumferential passage 130, by electric discharge machining or machining after forming a second central passage 1420 by casting in the circumferential passage forming first step S11 (a circumferential passage forming second step S21); and a third step of forming the circumferential end passages 150, 151 by electric discharge machining or machining (a circumferential passage forming third step S22). In addition, the electric discharge machining process S20 of several embodiments includes a trailing edge passage forming process S23 of forming the trailing edge passage 180.

In the second step S21 of forming the circumferential passage, an electrode for electric discharge machining, a tool for machining, or the like is inserted into the cavity 146 from the opening 145 of the second central passage 1420, and the electrode, the tool, or the like is moved obliquely toward the gas passage surface 25a in the direction of the leading edge 23a, and is moved in the circumferential direction Dc, thereby forming the first central passage 1410.

In the third circumferential passage forming step S22, after the processing in the second circumferential passage forming step S21 is completed, an electrode for electric discharge machining, a tool for machining, or the like is moved from the end face 251a of one side end 251 in the circumferential direction Dc of the inner shroud 25 (the side of the web-side blade surface 23 c) toward the other side end 252 (the side of the back-side blade surface 23 d) to one end of the first central passage 1410, thereby forming one circumferential end passage 150.

Similarly, in the third step S22 of forming the circumferential passage, the electrode for electric discharge machining is moved from the end face 252a of the other side end 252 (the back side blade face 23d side) toward the one side end 251 (the web side blade face 23c side) to the other end of the first central passage 1410, thereby forming the other circumferential end passage 151.

As described above, in the method of manufacturing the vane 21 according to the several embodiments, the step of forming the circumferential passage 130 in the inner shroud 25 includes: a first step S11 of forming a circumferential passage, a second step S21 of forming a circumferential passage, and a third step S22 of forming a circumferential passage.

In the trailing edge passage forming step S23, an electrode for electric discharge machining, a machining tool, or the like is moved from the trailing edge end surface 25c of the inner shroud 25 toward the leading edge 23a to the trailing edge side surface 1417 of the first central passage 1410, thereby forming the trailing edge passage 180.

The opening closing step S30 is a step of closing the opening 145 of the second central passage 1420 and the openings formed in the end surfaces 251a, 252a of the side end portions 251, 252 by electric discharge machining or mechanical machining in the third step S22 of forming the circumferential passage. In the opening closing step S30 of several embodiments, the lid 29 is fixed to the opening 145 of the second central passage 1420 by welding, and is closed. In the opening closing step S30 of several embodiments, the passage covers 150a and 151a are fixed by welding to the openings formed in the end surfaces 251a and 252a of the side end portions 251 and 252 by electric discharge machining or mechanical machining in the third step S22 of forming the circumferential passage, and the openings are closed.

According to the method of manufacturing the vane 21 of several embodiments, the trailing edge end passage 180 is formed such that the axial position of the upstream end 180b, at which the trailing edge end passage 180 is connected to the first central passage 1410, is arranged closer to the leading edge 23a than the position of the trailing edge side end surface 63a of the trailing edge side holder 63, at which the trailing edge side holder 63 is connected to the inner shroud 25, as the protruding portion. Therefore, the region of the inner shroud 25 near the gas passage surface 25a at the connection position between the inner shroud 25 and the trailing edge side holder 63 can be efficiently cooled by the cooling air flowing through the plurality of trailing edge portion passages 180 of the trailing edge portion 254 arranged in the circumferential direction. Therefore, the temperature in this region can be suppressed from being higher than in other regions, and the cooling effect of the inner shroud 25 of the vane 21 can be improved.

In addition, according to the method of manufacturing the vane 21 of several embodiments, the central passage 140 included in the circumferential passage 130 is formed to have the opening 145 at the trailing edge side end surface 63a of the retainer 63. In addition, in the circumferential cross section, the radially outer end (first top surface 1411) of the central passage 140 approaches the gas passage surface 25a and protrudes toward the front edge 23a side, and the radially inner end is formed at a position closer to the rear edge 23b than the radially outer end (first top surface 1411). Therefore, for example, in the case of manufacturing the vane 21 by casting, the opening 145 of the trailing edge side end surface 63a of the trailing edge side retainer 63 and the second central passage 1420, which is at least a part of the central passage 140 connected to the opening 145, are easily integrally formed during casting of the vane 21. This can suppress the manufacturing cost of the vane 21.

The characteristics of the manufacturing method in each step are as follows.

As described above, it is difficult to form the circumferential passage 130 on the trailing edge side holder 63 by casting, and further, it takes a long time as a processing time to form the circumferential passage 130 by electric discharge machining or mechanical machining, which is disadvantageous in terms of cost. Therefore, in the present embodiment, in the first step S11 of forming the circumferential passage, the second central passage 1420, which is a part of the circumferential passage 130, is formed by casting. In the second step S21 of forming the circumferential passage, the first central passage 1410, which is a part of the circumferential passage 130, is formed by electric discharge machining or machining. In the third step S22 of forming the circumferential passage, the circumferential end passages 150 and 151, which are part of the circumferential passage 130, are formed by electric discharge machining or machining. In the trailing edge passage forming step S23, the trailing edge passage 180 is formed by electric discharge machining or machining.

The position of the first central passage 1410 that constitutes a part of the circumferential passage 130 of the present embodiment requires a predetermined machining precision. That is, the upstream end 180b of the trailing edge end passage 180, which is connected to the trailing edge side surface 1417 of the first central passage 1410 on the axially upstream side, is preferably disposed as far as possible on the axially upstream side of the trailing edge side end surface 63a of the trailing edge side holder 63, and the first top surface 1411 on the outer side of the first central passage 1410 in the radial direction Dr is preferably formed as close to the gas passage surface 25a as possible. Therefore, when the first central passage 1410 is machined, a predetermined machining accuracy is required, and it is preferable to form the first central passage 1410 by machining or electric discharge machining.

The trailing edge passage 180 is configured such that a plurality of cooling holes 180a are arranged in the circumferential direction, and in order to uniformly maintain the circumferential metal temperature distribution of the trailing edge side holder 63 at the connection position with the inner shroud 25, it is preferable to form the aperture, the arrangement pitch, and the like of the cooling holes 180a with high accuracy. Therefore, a predetermined machining accuracy is required, and the trailing edge passage 180 is preferably formed by machining and electric discharge machining.

On the other hand, the second central passage 1420 does not require machining accuracy as compared with the first central passage 1410, but the volume of the cavity 146 is large, and the machining range and the machining capacity are large. Therefore, the second central passage 1420 is formed by casting, and the processing time can be reduced.

In addition, according to the method of manufacturing the vane 21 of the several embodiments, since a part of the circumferential passage 130 can be formed by casting, the number of parts formed by electric discharge machining or machining can be reduced, and the manufacturing cost of the vane 21 can be suppressed. According to the method of manufacturing the vane 21 of the present embodiment, by combining casting and electric discharge machining or machining, machining of the vane 21 becomes easy, and machining costs can be suppressed.

The present invention is not limited to the above-described embodiments, and includes a mode in which the above-described embodiments are modified and a mode in which these modes are appropriately combined.

Reference numerals illustrate:

a shield;

gas turbine;

turbine vanes (vanes);

wing-shaped part;

front edge;

trailing edge;

ventral blade surface;

back side blade face;

front end;

a base end;

inner shield;

gas passage surface;

trailing edge end face;

outside shield;

cover part;

61. leading edge side holder;

63. trailing edge side holders (protrusions);

trailing edge side end face;

front edge side end face;

crash panel;

71. through holes;

air passage;

110. Side access;

110a, 111 a;

110b, 111 b;

110c, 111c.

110e, 111e.

Circumferential passages;

central passage (inclined passage);

end part;

opening part;

cavity part;

150. circumferential end passages;

150a, 151a.

150b, 151b.

150c, 151c. trailing edge side end face;

150d, 151d.

150e, 151e.

150f, 151f.

150g, 151g.

150h, 151h.

Trailing edge end passage;

cooling holes;

an upstream end (first end);

another end (second end);

first trailing edge end passage;

second trailing edge end passage;

251. side end;

251a, 252 a..circumferential end faces;

253. leading edge end;

253a.

254. trailing edge end;

254a.

254b. trailing edge side lower end face;

inner region (space portion);

inner zone floor;

impact space;

257.

1410. a first central passage;

1411. a first top surface (third end);

1412. radially inner end (fourth end);

1415. leading edge side surfaces;

1417. trailing edge side surfaces;

1420.

1421. a second top surface;

1422. a connection opening;

1423. 1424. a circumferential end face;

1425. leading edge side end face;

1427.

Claims

1. A turbine vane, wherein,

the turbine vane includes:

wing-shaped parts;

the shield includes:

2. The turbine vane of claim 1, wherein,

the first end in the trailing edge end passage is connected with the circumferential passage at the axially upstream end.

3. The turbine vane of claim 1, wherein,

4. A turbine vane, wherein,

the turbine vane includes:

wing-shaped parts;

The shield includes:

5. The turbine vane of claim 4, wherein,

the central passage includes an inclined passage, a third end portion of which is close to the gas passage surface and protrudes toward a leading edge side in a cross section viewed from a circumferential direction, and a fourth end portion of which is formed at a trailing edge side from the third end portion and has an opening portion closed by a lid portion at a trailing edge side end surface of the protruding portion.

6. The turbine vane of claim 3 or 4, wherein,

the position in the blade height direction of the first end portion, at which the trailing edge end passage is connected to the circumferential passage, is closer to one side of the gas passage surface than the position in the blade height direction of the circumferential end passage.

7. The turbine vane of claim 3 or 4, wherein,

the central passage includes:

a first central passage formed on one side of the gas passage surface; and

and a second center passage formed on the outer side in the blade height direction from the gas passage surface than the first center passage, communicating with the first center passage, and including an opening formed on the trailing edge side end surface of the protruding portion.

8. The turbine vane of claim 7, wherein,

an axial position of an end portion of the first center passage on one side of the gas passage surface is closer to a leading edge side than an axial position at a connection position of the second center passage with the first center passage.

9. The turbine vane of claim 8, wherein,

10. The turbine vane of claim 7, wherein,

the opening of the second central passage extends from the trailing edge side end surface of the protruding portion to an end surface of the shroud opposite to the wing portion with the gas passage surface interposed therebetween.

11. The turbine vane of claim 1 or 4, wherein,

the shield includes:

12. The turbine vane of claim 1 or 4, wherein,

the shroud is an inner shroud formed on a distal end side of the wing, and an outer shroud formed on a proximal end side of the wing.

13. A gas turbine, wherein,

the gas turbine is provided with the turbine vane as claimed in any one of claims 1 to 12.

14. A method of manufacturing a turbine vane, wherein,

the turbine vane includes:

wing-shaped parts;

And forming a trailing edge end passage by the electric discharge machining or the machining, wherein a plurality of trailing edge end passages are arranged in a circumferential direction of a trailing edge side, a first end of the trailing edge end passage is connected to the first center passage, and a second end of the trailing edge end passage is opened to a trailing edge end surface of the shroud.

15. The method of manufacturing a turbine vane of claim 14 wherein,